Golfers and club designers have long recognized the advantages of clubs and putters with such undefined characteristics as "good feel" and "enlarged sweetspots." Some putter designers have used such methods as severe toe and heel weighting (creating high rotational moments of inertia around the putterhead center of gravity) to slightly reduce, but not eliminate, the effects of mishits on distance loss. "Mishits" as used herein occur when the actual ball strikepoint on the putter face occurs at some distance from the intended strikepoint. Others have used a uniform milled or cast slot behind the putterhead striking face to improve feel on mishits. However, such designs provide little or no actual distance loss improvement. Still others have used metalic or non-metalic inserts generally made with face materials as hard as or harder than a golf ball or golf ball cover (thus conforming with United States Golf Association (USGA) rules) which absorb impact vibrations thereby improving feel, again without improvement in mishit distance loss. Such inserts may have softer material behind the relatively hard face.
Scientific test results on popular putters using a putting robot were published in 1994 (Pelz, Golf Magazine 8/94: 64-65). This study quantified large distance losses resulting from mishits on the striking face. Toe/heel average distance loss for a 3/8 inch mishit on a 27 foot putt ranged from 2.85 feet (10.55%) for the worst designs (classical blades) to 1.85 feet (6.85%) for better designs (mallet head). It was determined through such testing that doubling the mishit distance (e.g., to 3/4 inch) approximately tripled the observed distance loss.
Golfers are, to a large extent, generally unaware of their average and maximum mishits during a round of golf. Large mishits are more likely on longer putts and, unfortunately, lead to the greatest percentage distance loss just when it is most critical to get the ball close to the hole to avoid 3 putt greens. It has been reported (Pelz, Golf Magazine 9/95: 64-65) that 3/4 inch mishits were not uncommon among average players and even accomplished players often have mishits greater than 3/8 inch. This data was determined through the use of impact decals affixed to the strikingface of putterheads.
None of the prior art putterhead designs eliminate or substantially reduce distance loss associated with mishit putts. A putterhead design which minimizes the distance loss associated with mishit putts would represent a substantial improvement in putterhead design. In addition, although Applicant is unaware of published test results conducted with golf clubs other than putters, the principles discussed above in connection with putters is equally applicable to other golf clubs (e.g., woods, irons and utility clubs).